在匀强磁场中做匀速圆周运动的带电粒子往往涉及区域限制性的临界问题.这类题目在高考中也会常常遇到,就其类型大致有以下几种:一、初速度 V_0大小一定。方向不确定例1 如图1所示,水平线 MN 下方存在垂直纸面向里的磁感应强度为 B 的匀强磁场,在 MN 线上某点 O Charged particles in a uniform magnetic field to make uniform circular motion are often involved in the critical issue of regional restrictions. Such topics will often be encountered in the college entrance examination, and its types are roughly the following: First, the initial speed V_0 size is certain. Uncertain Direction Example 1 As shown in Fig. 1, there is a uniform magnetic field with a magnetic induction intensity of B perpendicular to the vertical paper surface below the horizontal line MN, at a point on the MN line.